CN203744223U - Critical unit heating system - Google Patents

Abstract

The utility model provides a temporary heating system, which includes a water wall, a furnace water circulation pump, a deaerator and a steam drum. To the steam drum, the front wall of the boiler water wall is provided with a water discharge pipeline, and the boiler front wall water discharge pipeline is connected to the water supply pipeline of the deaerator through the connecting pipeline, and the steam connecting pipe of the deaerator is connected to the auxiliary steam of the machine. The utility model preheats the boiler water system by using the auxiliary steam of the auxiliary machine before the boiler is ignited, which improves the reliability and stability of the plasma ignition, greatly improves the burnout rate of the plasma ignition pulverized coal, makes it burn more fully, and reduces the The smoke and dust produced by combustion will pollute the atmospheric environment; at the same time, the startup speed of the boiler will be increased.

Description

A temporary heating system

technical field

The utility model relates to the field of thermal power generation equipment, in particular to an on-board heating system.

Background technique

Thermal power generation is the main power generation method in my country. As one of the three major main equipments of thermal power plants, power plant boilers develop along with the development of my country's thermal power industry.

The boiler is a kind of energy conversion equipment. The main working principle is to use the heat energy released after fuel combustion or the waste heat in industrial production to transfer to the water in the container, so that the water can reach the required temperature or steam at a certain pressure. The boiler is operated in two parts of the "pot" and "furnace" at the same time. After the water enters the boiler, the heating surface of the boiler in the steam-water system transfers the absorbed heat to the water, so that the water is heated into hot water at a certain temperature and pressure or steam is drawn out. application. In the part of the combustion equipment, the combustion of the fuel continuously releases heat. The high-temperature flue gas generated by the combustion transfers the heat to the heating surface of the boiler through heat transmission, and the temperature itself gradually decreases, and finally it is discharged from the chimney.

With the passage of time, environmental protection and energy conservation have become an important direction for the structural adjustment of China's electric power industry. Under the guidance of the policy of "increasing the large and suppressing the small", the thermal power industry is actively promoting the optimization and upgrading of the industrial structure, shutting down a large number of small thermal power units with low energy efficiency and heavy pollution, To a large extent, it has accelerated the upgrading of domestic thermal power equipment.

The existing boilers will cause certain pollution to the environment, one of the most important factors is: insufficient fuel combustion, especially in the early stage of boiler ignition and combustion, because the furnace cavity is relatively cold, the fuel combustion is not sufficient, and the resulting damage There are:

First of all, it increases the economic cost: insufficient fuel combustion increases the time from boiler ignition to grid connection, wasting fuel consumption.

Secondly, the safety performance is reduced: due to insufficient fuel combustion, the pulverized coal deposition in the tail flue of the boiler and the SCR area is greatly increased, and reburning in the tail flue is very easy to occur.

Finally, the stability of environmental protection equipment is reduced: due to insufficient fuel combustion, the deposition of pulverized coal in the denitrification catalyst and desulfurization tower is increased, resulting in a decrease in environmental protection efficiency after start-up.

Therefore, how to improve the burnout rate of fuel becomes very important.

Utility model content

In order to solve the above problems, the utility model provides a temporary heating system, specifically, the following technical solutions are adopted:

A temporary heating system, including a furnace, a deaerator and a steam drum, the water outlet of the deaerator is connected to the steam drum, and it is characterized in that, the front wall of the furnace is provided with a boiler front wall water discharge pipeline, and the front wall of the boiler The wall water discharge pipeline is connected to the water supply pipeline of the deaerator through the connecting pipeline, and the steam connecting pipe of the deaerator is connected to the auxiliary steam of the machine.

Further, a boiler water circulation pump is installed in the downpipe of the steam drum.

Further, a shut-off valve is set on the connecting pipeline.

Further, the boiler front wall drain pipeline is connected to the fixed-row expansion vessel, and a cut-off is set on the boiler front wall drain pipeline between the connecting pipeline and the boiler front wall drain pipeline and the fixed-row expansion vessel. valve.

Further, an electric shut-off valve and a manual shut-off valve are set on the boiler front wall water discharge pipeline before the connection of the connecting pipeline.

Further, the deaerator is connected to a low-pressure heater, and the low-pressure heater is arranged between the connecting pipeline and the deaerator; the deaerator is connected to a deaeration water tank.

Further, the deoxygenated water tanks are respectively connected to No. 1 high-pressure heater, No. 2 high-pressure heater and No. 3 high-pressure heater.

Further, the No. 1 high-pressure heater, the No. 2 high-pressure heater and the No. 3 high-pressure heater are all connected to the economizer, and the economizer is connected to the steam drum.

Further, the rear wall of the furnace is provided with a boiler rear wall water discharge pipeline, and the boiler rear wall water discharge pipeline is connected to a fixed row of expansion vessels.

Further, a manual shut-off valve and an electric shut-off valve are arranged on the water discharge pipeline on the rear wall of the boiler.

The utility model adopts a technical scheme different from the previous one. By using the temporary machine to preheat the furnace before the boiler is ignited, the reliability and stability of the plasma ignition are improved, and the burnout rate of the plasma ignition pulverized coal is greatly improved to make it burn More fully, reducing the pollution caused by the smoke generated by combustion to the atmospheric environment.

The water circulation system established by the utility model: add the connecting pipeline connecting the water discharge pipeline on the front wall of the boiler to the water supply pipeline of the deaerator, and lead the boiler water to the deaerator by correctly controlling the valve state of the relevant pipeline and relying on the static pressure inside the boiler , the water in the deaeration water tank is pumped back to the boiler drum again through the water supply pipeline by a pre-steam pump, so that the water in the water wall of the boiler is repeatedly circulated to provide the possibility for continuous heating.

The utility model adopts the adjacent machine to provide continuous heat source: after the water circulation is established, use the auxiliary steam from the adjacent machine, put it into the deaerator for heating, continuously strengthen the water coming from the front wall of the boiler, and slowly increase the water temperature in the entire furnace, thereby gradually increasing the temperature in the furnace.

The utility model guarantees the forced circulation of boiler water: in order to ensure uniform heating of each water-cooled wall pipe of the boiler and accelerate the temperature rise of the boiler tube wall, the boiler water circulation pump is started after being put into the heating system, so as to speed up the exchange of high and low temperature water heat in the water-cooled wall and avoid uneven heating. Generate excessive thermal stress and thermal deformation.

Due to the adoption of the above-mentioned technical scheme, the utility model effectively solves the technical problem that the furnace of the existing boiler is relatively cold before ignition, so that the utility model has the following advantages:

1. Improve economy: Heating before ignition improves the reliability and stability of plasma ignition, improves the burnout rate of pulverized coal in plasma ignition, and can greatly shorten the time from boiler ignition to grid connection, saving fuel consumption.

2. Improve safety: After the burnout rate of plasma ignition pulverized coal is improved, the deposition of pulverized coal in the tail flue of the boiler and the SCR area is greatly reduced, and reburning in the tail flue is prevented.

3. Increase the stability of environmental protection equipment: After the burnout rate of plasma ignition pulverized coal is improved, the deposition of pulverized coal in the denitrification catalyst and desulfurization tower is greatly reduced, and the environmental protection efficiency is prevented from being reduced after startup.

Description of drawings

Fig. 1 is the system diagram of the utility model.

Explanation of numbers in the attached drawings: 1-furnace 2-boiler water circulation pump 3-boiler back wall water discharge pipeline 4-boiler front wall water discharge pipeline 5-fixed row expansion vessel 6-connecting pipeline 7-fixed drainage pool 8-first High-pressure heater 9-second high-pressure heater 10-third high-pressure heater 11-coal economizer 12-deaerator 13-deoxygenated water tank 14-low pressure heater 15-steam drum.

Detailed ways

As shown in Figure 1, a kind of temporary machine heating system of the present utility model comprises furnace 1, deaerator 12 and steam drum 15, and the water outlet of described deaerator 12 is connected to steam drum 15, is characterized in that, the The front wall of the furnace 1 is provided with a boiler front wall water discharge pipeline 4, and the boiler front wall water discharge pipeline 4 is connected to the water supply pipeline of the deaerator 12 through the connecting pipeline 6, and the steam connecting pipe of the deaerator 12 is connected to the auxiliary machine. steam.

In order to ensure the water circulation of the utility model, a boiler water circulation pump 2 is arranged in the descending pipeline of the steam drum 15 of the utility model, and the water circulation power is provided by the boiler water circulation pump 2 .

The utility model has been modified on the connecting pipeline of the existing boiler: firstly, the water discharge pipeline 4 on the front wall of the boiler and the deaerator 12 are connected through a connecting pipeline 6 to establish a boiler water cycle; secondly, through the original The boiler water circulation pump 2 installed in the descending pipeline of the steam drum 15 provides power for the water circulation, so that the water circulation can be carried out compulsorily; finally, after the water circulation is established, the auxiliary steam is used to supply steam from the machine, and it is put into the deaerator 12 for heating. The water from the wall slowly increases the water temperature in the entire water-cooled wall, thereby gradually increasing the temperature in the furnace.

When the system of the utility model is put into use, it is necessary to ensure that the water levels of the deaerator 12 and the steam drum 15 are stable. The water level of the bag is balanced to prevent the overflow valve action caused by the high water level of the deaerator. Therefore, the utility model is provided with corresponding valves to control the flow.

First, in order to control the flow in the connecting pipeline 6, a cut-off valve, preferably a manual shut-off valve, is provided on the connecting pipeline 6 .

Secondly, the boiler front wall discharge pipeline 4 of the utility model is connected to the fixed row expansion container 5, in order to realize the flow control of flowing into the fixed row expansion container 5 in the boiler front wall water discharge pipeline 4, the connecting pipeline 6 and the boiler A shut-off valve is arranged on the boiler front wall drain pipeline 4 between the junction of the front wall drain pipeline 4 and the fixed row expansion vessel 5, preferably a manual shut-off valve.

Finally, in order to realize the total flow control in the water discharge pipeline 4 of the boiler front wall, an electric cut-off valve and a manual cut-off valve are arranged on the water discharge pipeline 4 of the boiler front wall before the connection of the connecting pipeline 6 .

The valves on the original pipeline and equipment are kept unchanged to realize the monitoring of the flow in the water circulation process.

The deaerator 12 of the utility model is connected with a low-pressure heater 14 , and the low-pressure heater 14 is arranged between the connecting pipeline 6 and the deaerator 12 .

The role of the low-pressure heater is to use the steam that has done part of the work in the steam turbine to pump it into the heater to heat the feed water, increase the temperature of the water, reduce the amount of steam discharged from the steam turbine to the condenser, reduce energy loss, and improve Cycle efficiency of thermal systems. The structure is more vertical tube plate heater. The heating surface of the heater is generally composed of straight tube bundles or U-shaped tube bundles made of brass tubes or seamless steel tubes. The heated water enters the side of the separated water chamber from the upper water inlet pipe, and then flows into the U-shaped tube bundle. The U-shaped tube is in the steam space of the heater, absorbs the heat of the heating steam, and is transferred to the water flowing in the tube by the tube wall. , the heated water flows out through the heater outlet water chamber.

The deaerator 12 of the utility model is connected with a deaeration water tank 13 . The deoxygenated feed water is collected into the lower container of the deaerator, that is, the deaeration water tank. The deaeration water tank is equipped with the latest scientifically designed powerful heat exchange reboiling device. Reduce the vibration of the water tank, reduce the accent and other advantages, improve the service life of the equipment, and ensure the safety and reliability of the equipment operation.

The oxygen-removing water tank 13 is respectively connected with No. 1 high-pressure heater 8, No. 2 high-pressure heater 9 and No. 3 high-pressure heater 10.

The high-pressure heater is a device that uses the partial extraction of the steam turbine to heat the feed water. The device is composed of two parts, the shell and the pipe system. The steam condensing section is set on the upper part of the inner cavity of the shell, the drain cooling section is set on the lower part, and the water supply inlet and water supply outlet are set at the top of the inlet and outlet pipes. When the superheated steam enters the casing from the inlet, it can heat the feed water in the upper main coil, and after the steam condenses into water, the condensed hot water can heat part of the feed water in the lower cooling coil, and the condensed water after being used is passed through The hydrophobic outlet flows out of the body. The device has significant advantages such as low energy consumption, compact structure, less occupied area, low material consumption, etc., and can strictly control the water level of the drain, the flow rate of the drain and reduce the difference of the drain end.

No. 1 high pressure heater 8 , No. 2 high pressure heater 9 and No. 3 high pressure heater 10 are all connected to economizer 11 , and economizer 11 is connected to steam drum 15 .

The back wall of the furnace 1 of the utility model is provided with a boiler back wall water discharge pipeline 3, and the boiler back wall water discharge pipeline 3 is connected to a fixed row expansion vessel 5. A manual shut-off valve and an electric shut-off valve are arranged on the water discharge pipeline 3 on the boiler rear wall.

The water discharge pipeline of the low-pressure heater 14 of the utility model is connected to the fixed drainage pool 7, and a manual shut-off valve is set on its water discharge pipeline.

The method that the utility model starts:

(1) Confirm that the water quality of the deaerator 12 is qualified and has been put into the heating system, carefully check the status of each valve according to the inspection standard before boiler water filling, confirm that the boiler water pump is filled with water, start a pre-steam pump to fill the boiler steam drum 15 to high water level.

(2) After the boiler is filled with water, start the boiler water circulation pump 2 to exhaust, and the boiler water circulation pump 2 circulates the boiler water.

(3) Confirm that the electric door at the outlet of the low-pressure heater 14 on the machine side is open, the entrance door of the low-pressure heater 14 is closed, the electric door and the manual door of the low-pressure heater 14 are fully open, all the drain valves of the condensate pipes are closed, and the high-pressure heater drains to The fixed row door is closed, and the manual door is closed when the smoke cooler discharges water to the fixed row; confirm that the manual door is closed from the low pressure heater 14 on the furnace side to the fixed drainage pool, and the connection door from the front wall water discharge pipeline 4 to the low pressure heater 14 water discharge pipeline is closed. The front wall water discharge pipeline 4 is closed to the fixed row expansion container 5 manual door.

(4) Slowly and fully open the water discharge electric door and manual door on the front wall of the boiler, and gradually open the front wall to discharge water to the connection door of the low pressure heater 14 water discharge pipe, confirm that the water level of the deaerator 12 rises slowly, and control the electric door at the entrance of the economizer 11 Gradually increase the output of the front pump, and control the water level of the deaerator 12 and the water level of the steam drum 15 to be stable.

(5) After the water cycle is established, try to increase the flow rate of the water cycle, gradually increase the auxiliary steam supply of the deaerator 12, slowly control the temperature of the furnace water to rise gradually, and gradually increase the temperature of the furnace water to about 120 °C. During the period, it is required to control the water level of the steam drum 15, the water level of the deaerator 12 is normal, and when the water level of the deaerator 12 is low, start the boiler water pump to maintain.

Requirements of the utility model:

(1) Before the boiler is ignited, the boiler is required to prohibit ventilation. After the temperature of the furnace reaches the requirement, it should be confirmed that the heating pipe of the heater is sufficient and the plasma ignition system is fully prepared, and then start the induced draft fan, and it is required to complete the plasma ignition as soon as possible to prevent excessive stress caused by the sudden cooling of the furnace.

(2) After filling the steam drum with water, make sure that the water quality of the furnace is qualified (add water for the last time), so as to prevent the nozzle of the deaerator from being blocked due to too dirty water quality.

(3) Pay attention to monitoring the water level and water temperature changes of the deaerator during heating to prevent overpressure of the deaerator, and the valves used should be able to close tightly during operation.

(4) After exiting the temporary heating system, be sure to fully open the manual door for draining water from the front wall to the fixed drainage tank and the fixed drainage pool, so as to prevent lame pressure and damage to the equipment caused by lame pressure on the front wall water gate after the unit is started.

After a certain power plant adopts the technical solution of the utility model, it has the following technical effects:

(1) The heating system was put into operation at 13:47 on November 24 and shut down at 0:37 on the 25th. It was put into operation for a total of 11 hours, of which the circulating water volume of the entire system was about 180-190 tons/hour, and the furnace water temperature rose by 36°C, saving The smoke temperature at the coal burner outlet rises by 47°C, and the furnace water rises by an average of 3°C per hour. If the wind and smoke system is out of operation (the ventilation volume of the wind and smoke system in this test is about 700 cubic meters per hour), it is estimated that it will take 12 hours to increase the temperature of the furnace water from 20°C to 150°C at this speed.

(2) After the furnace temperature is increased from 20°C to 60°C, the plasma ignition is stable and the burnout rate of the plasma is greatly improved, which not only greatly shortens the start-up fuel consumption and start-up time, but also alleviates the deposition of pulverized coal in the tail flue and desulfurization The pulverized coal deposition in the tower and SCR area has played the expected effect.

The above descriptions are only preferred embodiments of the present utility model, and do not limit the utility model in any form. Although the utility model has been disclosed as above with preferred embodiments, it is not intended to limit the utility model. Without departing from the scope of the technical solution of the utility model, the technicians of this patent may use the technical content of the above prompts to make some changes or modify them into equivalent embodiments with equivalent changes, but all do not depart from the content of the technical solution of the utility model Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the utility model still belong to the scope of the solution of the utility model.

Claims (10)

1. A temporary heating system, comprising a furnace (1), a deaerator (12) and a steam drum (15), the water outlet of the deaerator (12) is connected to the steam drum (15), characterized in that , the front wall of the furnace (1) is provided with a boiler front wall water discharge pipeline (4), and the boiler front wall water discharge pipeline (4) is connected to the water supply pipeline of the deaerator (12) through the connecting pipeline (6), The steam connecting pipe of the deaerator (12) leads into the auxiliary steam of the machine. 2. A temporary heating system according to claim 1, characterized in that a boiler water circulation pump (2) is installed in the downpipe of the steam drum (15). 3. The emergency heating system according to claim 1, characterized in that a cut-off valve is set on the connecting pipeline (6). 4. A temporary heating system according to claim 1, characterized in that the water discharge pipeline (4) on the front wall of the boiler is connected to the fixed row expansion vessel (5), and the connecting pipeline (6) is connected to the A cut-off valve is set on the boiler front wall water discharge pipeline (4) between the joint of the boiler front wall water discharge pipeline (4) and the fixed row expansion vessel (5). 5. A temporary heating system according to claim 4, characterized in that an electric shut-off valve and a manual shut-off valve are set on the water discharge pipeline (4) on the boiler front wall before the connection of the connecting pipeline (6). 6. A temporary heating system according to claim 1, characterized in that the deaerator (12) is connected to a low-pressure heater (14), and the low-pressure heater (14) is arranged on the connecting pipeline (6) Between the deaerator (12); the deaerator (12) is connected to the deaerator water tank (13). 7. A temporary heating system according to claim 6, characterized in that the deoxygenated water tank (13) is respectively connected to No. 1 high pressure heater (8), No. 2 high pressure heater (9) and No. 3 high pressure heater High pressure heater (10). 8. A temporary heating system according to claim 7, characterized in that the No. 1 high-pressure heater (8), the No. 2 high-pressure heater (9) and the No. 3 high-pressure heater (10) are all connected to To the economizer (11), the economizer (11) is connected to the steam drum (15). 9. A temporary heating system according to claim 1, characterized in that, the rear wall of the furnace (1) is provided with a boiler rear wall water discharge pipeline (3), and the boiler rear wall water discharge pipeline (3 ) to connect the fixed row expander (5). 10. A temporary heating system according to claim 9, characterized in that a manual cut-off valve and an electric cut-off valve are arranged on the water discharge pipeline (3) on the rear wall of the boiler.